1. Field of the Invention
The invention concerns a sorting machine of enhanced throughput of the type used in sorting mail. However, a machine of this kind may find applications in other fields, in particular in banks for sorting cheques, and generally speaking it may be utilized wherever the problem is raised of distributing batches of objects in large numbers according to their destination.
2. Description of the Prior Art
In the mail field, a sorting machine comprises an injector linked under the control of a control circuit to a plurality of parallel sorting lines. The injector comprises a magazine in which the objects to be sorted are stacked, an extractor to extract the objects one by one from the magazine, and a detector unit adapted to recognize the destination to which each object must be addressed as the objects are extracted. The control circuit receives the detected signals and produces sorting instructions which it sends to the sorting lines. Each sorting line comprises a plurality of receptacles each of which is assigned to a particular destination. The set of receptacles for all the sorting lines covers all possible destinations to which each of the objects may be addressed.
Sorting machines are designed with a nominal throughput. The injector is designed to operate at this nominal throughput. For the machine to operate in a coherent manner it is necessary that the theoretical nominal throughput of each sorting line be at least equal to the nominal throughput of the injector. A single one of the sorting lines is selected for each object sorted. This means that, independently of the speed with which one sorting line is selected from the set of sorting lines, there may be an underutilization of all the sorting lines which have not been selected. There are known sorting machines with eight parallel sorting lines each comprising 24 receptacles. Thus of the 192 possible destinations, only the 24 associated with one sorting line are selected at any particular time. Consequently, all the others are temporarily inoperative. The most expensive units of a sorting machine are the sorting lines and although the nominal throughput of each of them is equal to the throughput of the injector, broadly speaking their actual throughput is multiplied by a factor of 1/N, where N is the number of lines in the machine.
An object of the invention is to alleviate the cited disadvantages by offering a machine equipped with at least one supplementary injector placed in parallel with the first and feeding into the sorting lines. To resolve theproblems of conflicting destinations which arise when two objects from the injectors are intended for the same sorting line, the invention provides for the disposition between these injectors and the sorting lines of means for eliminating any conflict.